Which term describes an abnormal mass that varies in size, shape, and color?

The term that describes an abnormal mass that varies in size, shape, and color is "tumor." Tumors can be classified as benign or malignant, and they can manifest in various forms across different tissues within the body. The variability in their appearance, including size and color, is characteristic of tumor growth. These masses arise when cells begin to grow uncontrollably, leading to the formation of abnormal tissue.

In this context, while the terms growth, cyst, and lesion are related, they do not encapsulate the full spectrum of variability associated with tumors. A growth refers generally to any additional tissue that has formed, which may not always have the distinct features of a tumor. A cyst is a sac-like structure that typically contains fluid or semi-solid material, usually well-defined, but does not necessarily denote the variability in appearance that tumors may exhibit. A lesion refers to any abnormal tissue area resulting from injury or disease, but again, this term does not specifically imply the broad characteristics of size and color variability found in tumors. Thus, "tumor" is the most accurate choice in describing an abnormal mass with these specific features.